Abstract: This study aimed at investigating effects of the clear-cutting on methane flux. The study was carried out in the beach of Yangtze River in Junshan, Yueyang City, and the data of methane flux was collected with static chamber–FMA (fast methane analyzer) approach. Compared observations of methane flux and the environmental factors (soil temperature, soil water content and herbaceous vegetation) were carried out in the clear-cut field and uncut field. The result showed that the whole area was a sink of methane in the fast growing seasons in unflooded year, and that clear-cutting leaded to significant (P<0.001 andP<0.05) declines of methane uptake rates. Twice observations showed that the rates in the clear-cut field were only 29% and 22% of the uncut field in the early two months after clear-cutting, respectively. The clear-cutting also changed diurnal pattern of methane uptake rates. The clear-cutting significantly reduced methane sink probably through the clear-cutting induced changes in soil temperature, soil water content, and the vegetations.

Key words: methane flux, clear-cutting, Populus deltoides plantation, fast methane analyzer (FMA), static chamber, beach land of Yangtze River